This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A249279 #9 Oct 27 2014 09:36:19 %S A249279 0,7,1,8,2,9,3,10,4,11,12,15,16,19,20,23,24,27,28,31,5,6,13,14,17,18, %T A249279 21,22,25,26,32,35,36,39,40,43,44,47,48,51,29,30,33,34,37,38,41,42,45, %U A249279 46,52,55,56,59,60,63,64,67,68,71,49,50,53,54,57,58,61,62,65,66,72,75,76 %N A249279 Inverse permutation of A249278 (such that first digit of a(n+1) has parity of a(n)). %H A249279 Reinhard Zumkeller, <a href="/A249279/b249279.txt">Table of n, a(n) for n = 0..10000</a> %H A249279 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A249279 (PARI) N=100;vector(N,n,t=0;for(i=1,#A249278,A249278[i]==n-1&&(t=i)&&break);t-1) %o A249279 (Haskell) %o A249279 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A249279 a249279 = fromJust . (`elemIndex` a249278_list) %o A249279 -- _Reinhard Zumkeller_, Oct 27 2014 %K A249279 nonn %O A249279 0,2 %A A249279 _M. F. Hasler_, Oct 24 2014